The present invention relates to high temperature furnaces and more particularly to a furnace which will permit the heating of specimens to temperatures in the region of 2000 degrees centigrade in a non-neutral or oxidizing atmosphere.
While various furnace constructions are known in the art which will permit operation to temperatures approaching 2000 degrees centigrade, these designs typically require that the entire heating region be bathed in a non-reactive gaseous atmosphere such as nitrogen or argon. An example of a furnace of this type is that shown in the Anderson et al. patent 3,128,325.
Where it has been desired to heat specimens in a non-neutral or oxidizing atmosphere, prior art designs have typically provided a so-called muffle tube which surrounds the specimen or heat treatment region and which protects the heating elements from the oxidizing or reactive atmosphere. The muffle tube itself, however, tends to insulate the specimen from the source of heat and it has thus not been possible with these prior art designs to reach temperature in the region of 2000 degrees centigrade.